The tense meeting between Barack Obama, the US president, and Benjamin Netanyahu, Israeli prime minister, this week was a vivid reminder of the formidable obstacles in the way of Middle East peace. Even so, there are some Arab-Israeli minefields that can be traversed with a pragmatic compass: including the fate of the roughly 5m Palestinian refugees – used by rejectionists on both sides to argue that no reconciliation of this tragic history will ever be possible.

The Palestinian refugees – who fled or were driven out by the 1948 and 1967 wars – and the Palestine Liberation Organisation, insist on their right of return. According to the United Nations Relief and Works Agency (UNRWA) responsible for their welfare, the number of refugees is about 4.5m. Israel opposes their return, arguing that it would irreversibly change the demographic balance of the Jewish state. This is a real concern, so it would be as well to examine the reality.